If you conquer a battlefield, then retreat and return to conquer that same battlefield again on the same turn, do you get the point again and do field abilities (like Candlelit Sanctum) trigger?

Ruling: You cannot score a battlefield more than once per turn. When you close the second showdown after moving back to a previously scored battlefield, you will not score a point and thus will not conquer. No conquer effects will trigger.

Nuances:

• Conquering is a type of scoring, not a separate step that happens after scoring
• If you conquer but cannot get a point (like when you're at 7 points), you still get conquer effects
• If you take control of a battlefield you've already scored that turn, you don't conquer at all, so no effects trigger
• You can still win on your 8th point via conquering, as long as you've scored every other battlefield that turn